A prior art vehicle transmission assembly is known from JP, A No. 59-106322 in which a differential-locking clutch is operated in response to the actuation of a brake for braking the vehicle. In this case, a differential gearing with which the locking clutch is associated is disabled by the operation of locking clutch so that the vehicle is stopped necessarily at its straight travel condition whereby safety is secured. The transmission assembly disclosed in the Japanese publication set forth above is fashioned such that the differential-locking clutch is operated exclusively by a brake-actuating device for the brake.
In a case where this prior art is applied to a vehicle transmission assembly including a differential-locking clutch of a positive clutch type which comprises mutually interlocable clutch members of one and the other sides, these clutch members may cause a slipping contact with each other if the clutch members are not in a proper alignment of causing an interlocking between them when the locking clutch is operated by a brake-actuating device. When this is caused, operation of the brake-actuating device to its final position where it actuates the brake fully is delayed so that the braking distance of vehicle is prolonged.
Further, a differential gearing provided in a working vehicle which is often traveled on grounds of bad trafficability is often required or desired to be disabled. The differential-locking clutch which is operated exclusively by a brake-actuating device will not permit the differential gearing to be disabled at a non-actuated condition of the brake.
Accordingly, a primary object of the present invention is to provide an improved vehicle transmission assembly of the type set forth above in which a differential-locking clutch is operated by a brake-actuating device without causing any delay of the full actuation of brake whereby a short braking distance of the vehicle is assured.
An attendant object of the present invention is to provide a vehicle transmission assembly in which the locking clutch is operatively connected to the brake-actuating device so as to permit an independent operation of the locking clutch by means of a separate clutch-operating device.